I have some H4831 that I bought for fifty two cents per pound back in the mid 1960's. It has been stored in an unheated garage in a dark closet in tin cans. It still performs, so far as I can determine, as it did when I bought it. Ditto for some H4895 that I bought in the mid 1970's for a dollar a pound. It was stored the same way the H4831 was stored, and it performs as it always has. I live in a semi-desert zone east of the Cascade Mountains in Oregon.
Whoever told you that you should smell the powder, and trash it if it smells bad, was spot on. Look also for some red rusty looking dust in the powder. Those are bad signs, and probably a signal that it should be used as fertilizer in your garden or flower beds. If it has a smell sort of like ether, and it shows none of the characteristics previously warned against, use it.